Dichlorido(dimethylformamide-κO)[1,4,7-tris(2-cyanoethyl)-1,4,7-triazacyclononane-κ3 N 1,N 4,N 7]nickel(II)

The title complex, [NiCl2(C15H24N6)(C3H7NO)], is isomorphous with the CoII analogue. Three N-atom donors from the facially coordinating triaza macrocyclic ligand, one O-atom donor from dimethylformamide and two Cl− anions surround the NiII ion in a distorted octahedral coordination geometry. Intermolecular C—H⋯Cl and C—H⋯N hydrogen-bonding interactions link the complex molecules into a three-dimensional supramolecular architecture.

The title complex, [NiCl 2 (C 15 H 24 N 6 )(C 3 H 7 NO)], is isomorphous with the Co II analogue. Three N-atom donors from the facially coordinating triaza macrocyclic ligand, one O-atom donor from dimethylformamide and two Cl À anions surround the Ni II ion in a distorted octahedral coordination geometry. Intermolecular C-HÁ Á ÁCl and C-HÁ Á ÁN hydrogen-bonding interactions link the complex molecules into a three-dimensional supramolecular architecture.
As depicted in Fig. 1 Schlager et al. 1995), indicating that the coordination geometry around Ni II is slightly distorted from regular octahedral.
All bond lengths around Ni II ion (Table 1) are comparable to those observed in related Ni II complexes (Graham et al. 2005;Li et al. 2005). Pendant 2-cyanoethyl groups attached to the [9]aneN 3 framework are not involved in the coordination to the Ni II center and point away from the macrocyclic cavity.
Two coordinated Clanions participate in the formation of multiple C-H···Cl hydrogen bonds (Table 2), which serve to link the complexes into two-dimensional sheets parallel to (010). These sheets are further connected through C-H···N hydrogen bonds, generating a three-dimensional supramolecular network (Fig. 2).

Refinement
All H atoms were placed in calculated positions and treated in the subsequent refinement as riding atoms, with C-H distances in the range 0.93-0.97 Å and U iso (H) = 1.2 U eq (C) or 1.5 U eq (methyl C).